In-situ, real-time, and non-destructive tracking of chloride erosion in concrete using flexible all-solid-state sensors for structural health monitoring

With the completion of many large-scale projects in coastal areas, the durability deterioration of reinforced concrete caused by various erosion factors has become increasingly prominent. Therefore, it is very important to develop in-situ, real-time and non-destructive monitoring technology for these ions. Here, we report a high-performance, flexible and all-solid-state chloride ion sensor fabricated by inkjet printing. Optimization of ink formulation, droplet-assisted printing, design of a unique functional interlayer interface structure, and precise control of active materials loading achieved excellent sensor characteristics. The sensor demonstrated excellent sensitivity, selectivity, repeatability, stability and quick response in chloride ion quantification. We confirmed the sensor's reliability and potential for on-site durability evaluation through successful real-time monitoring. The sensor accurately tracked the chloride ion concentration and distribution within the pore solution of cement specimens. The sensor design strategy also demonstrated the scalability for monitoring various erosion ions. This work provides a novel method that establishes a foundation for advancing the monitoring and maintenance of smart concrete infrastructure.